Study on Vision Takes Hard Look at Digital Screens
Americans are constantly connected and staring at digital screens—be they cellphones, tablets, computers or TVs. Many times, multiple devices are being used at once.
This constant exposure is taking a toll: More than half of Americans report feeling digital eyestrain–discomfort caused from using digital devices. When more than one device is used, 75 percent report discomfort.
What is digital eyestrain?
The American Optometric Association defines digital eyestrain, also known as computer vision syndrome, as “a group of eye and vision-related problems that result from prolonged computer, tablet, e-reader and cellphone use.” The association does not specify what it considers a prolonged length of time, but says as digital screen use increases, so does discomfort.
Common symptoms of digital eyestrain include:
- Blurred vision
- Dry eyes
- Neck and shoulder pain
Symptoms can be caused by poor lighting, glare on a digital screen, improper viewing distance, poor posture, existing eye condition, or a combination of these factors, according to AOA.
“These symptoms—headaches, eyestrain, fatigue—will be caused by any excessive amount of close work. Our bodies are not meant to do it,” said Dr. Valerie Kattouf, associate professor; chief of pediatrics/binocular vision service at the Illinois Eye Institute. “Our focusing system has to be able to work up close and then relax when we look far away, so we really damage that when we work up close. It causes us to lock up and it just can’t relax.”
Of those who experience digital eyestrain, women are more likely to report symptoms than men. Women are also more likely to use multiple screens at the same time, with 74 percent of women multitasking on their digital devices compared to 67 percent of men.
All ages are effected by digital eyestrain including children, who have more focusing power than adults.
“Kids have a huge amount of focusing power, but they do so much excessive close work that they start to lose focusing power at a very young age,” she said. “They get headaches, eyestrain, discomfort with reading, and they tend to get really close when they do things because they can’t see at a normal distance.”
In her 20 years of practice, Kattouf says she’s seen an increase in children experiencing digital eyestrain with the rise and proliferation of digital devices.
“I see it more often. I see it in younger patients. Sometimes you don’t expect it in 5- and 6-year-olds, but we do see it,” she said. “Parents are telling us that they’ve been on this iPad since they were 2 years old. We’ve never had a generation experience this before.”
In fact, 70 percent of surveyed parents who let their children use devices for three or more hours a day said they were concerned about the impact of these devices on their children’s eyesight.
Why are these devices harmful?
Powering down for the day doesn’t mean unplugging from technology: 76 percent of Americans look at their digital devices in the hour before going to sleep. For Millennials—adults in their 20s—nearly 90 percent check their devices before bed, according to the report.
Digital devices emit high-energy visible light, commonly referred to as “blue light,” which is near the ultraviolet (UV) end of the spectrum and also found in sunlight.
Blue light wakes people up by signaling the brain to suppress the sleep hormone melatonin and produce cortisol, a hormone that increases wakefulness. A 2014 study revealed an association with blue light exposure and sleep problems. According to an AOA article, one week of increased exposure to blue light before sleep decreased sleep time by an average of 14 minutes.
The use of such devices before bed "prolongs the time it takes to fall asleep, delays the circadian clock, suppresses levels of the sleep-promoting hormone melatonin, reduces the amount and delays the timing of REM sleep, and reduces alertness the following morning," according to a January 2015 study in the Proceedings of the National Academy of Sciences.
For Kattouf, the devices themselves aren’t the problem but the way in which we use them.
“Those things aren’t the root of the problem. It’s the excessive amount of time we spend on them,” she said.
Tips for preventing digital eyestrain
Follow the 20-20-20 rule, says the AOA: Take a 20-second break from digital devices every 20 minutes by looking at something 20 feet away.
“Like everything, we need moderation,” Kattouf said. “Parents of school-age kids have to have rules that establish when they can use [digital devices] and when they can’t. And as adults we have to set standards for ourselves. There have to be digital-free zones or digital-free times.”
Kattouf also recommends people of all ages receive yearly comprehensive eye exams by optometrists who treat accommodative and binocular vision disorders.
Listed below are more tips from the AOA and the Vision Council:
- Wear eyeglasses for computer viewing. Glasses and contacts prescribed for regular use may not suffice for using digital devices. Special lens designs, powers or tints/coatings can help.
- Vision therapy may be needed for symptoms that can’t be addressed with special eyewear.
- Make your workspace easy on the eyes. Place computer screens 20-28 inches (about an arm’s length) away from you and position them slightly below eye level (about 4 to 5 inches) as measured from the center of the screen. Position your chair so your feet rest flat on the floor. If your chair has arms, set them so they support you while you type, and while you’re typing keep your wrists elevated—they shouldn’t rest on the keyboard.
- Blink. Blinking keeps eyes moist, so make an effort to blink frequently.
- Use proper posture while using devices. Don’t strain your neck to look at your phone in your lap (or under your desk). Position the device just below eye level at a comfortable distance from your face.
- Minimize glare. Arrange your computer to avoid glare from lights and windows. If this isn’t an option, use a screen glare filter, which decreases the amount of light reflected from the screen.
Follow Kristen Thometz on Twitter: @kristenthometz
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